p53 nuclear overexpression: an independent predictor of survival in lymph node--positive colorectal cancer patients.

This study was performed to determine the prognostic significance of p53 gene overexpression in a homogeneous group of node-positive colorectal cancer patients. Paraffin sections from the primary tumors in 107 colorectal cancer patients who had preoperative serum carcinoembryonic antigen (CEA) levels less than five were examined for the expression of p53 nuclear protein by immunohistochemical staining using the monoclonal antibody PAb 1801. The nuclear p53 overexpression was compared with clinicopathologic variables and follow-up data. Positive staining was not observed in normal colorectal mucosal cells. Specific p53 nuclear staining was detected in primary tumor from 50 patients (46.7%). p53 nuclear overexpression was not significantly correlated with patients' sex, age, tumor location, differentiation, T stage, N stage, and lymphatic and/or vascular vessel invasion. With a median follow-up of 61.7 months, 60% of the p53-positive patients have had disease recurrence, versus only 35% of the p53-negative group (P = .02). Forty-two percent of the p53-positive patients died of colorectal cancer compared with 21.1% of the p53-negative patients (P = .03). By multivariate analysis, p53 overexpression was found to be an independent predictor for disease-free and disease-specific survival. In node-positive colorectal cancer patients with low preoperative CEA levels, nuclear p53 overexpression as determined by immunohistochemistry on archived tissue is an independent predictor for prognosis.